When I say "switch off" a particular section, if you look at the SysEx message for the style's "Section Control" on page 83 of the PSR-A3000's Data List, one of the parameters in that message is a switch which can be set to an "On" or "Off" status. As I said, my PSR-E models don't seem to respond to these style-related SysEx messages, so I have absolutely no personal experience with them-- but I would guess that the way you change from one section to another is to send the message which switches on the section you want to change to, and that whatever section was previously being played will automatically switch off as the new section switches on. And I don't know whether manually switching off the current section without switching on a new section will cause the style playback to stop, but that's what I'm suggesting you try.